Americans don't eat much cassava (with the exception of tapioca), but it's a food staple elsewhere around the globe. The tuber, also called yucca or manioc, is grown around the globe but is most densely grown in equatorial Africa, South America and Asia. This nutrient-dense food is a staple for hundreds of millions of people and it's the crop of choice for countless farmers, particularly in Africa where most subsistence farmer grow it.
Cassava faces an uncertain future due to a germ called the African cassava mosaic virus, or ACMV. ACMV causes the cassava leaves to fall off and is spread by the whitefly and when affected plants are transplanted to new fields. The virus began as a genetic mutation somewhere in Uganda in the 1980s and is estimated to be spreading at a rate of 50 miles per year. It has already hit Rwanda, Burundi, the French-speaking Democratic Republic of Congo and the Republic of Congo.